The present invention relates to an apparatus for the continuous production of expanded plastics panels with inserts on the longitudinal edges thereof.
It is known that plants for the continuous production of low-density rigid foam panels for thermal insulation which have a rectangular or otherwise variously shaped cross-section, have long been commercially available.
Said panels are manufactured by inserting between two layers a liquid reactive mixture which is usually constituted by reagents such as isocyanate and polyol, water, catalysts and the like and by optional blowing agents, such as hydrocarbons, hydrochlorofluorocarbons, hydrofluorocarbons and the like.
Within a few seconds, the reactive mixture starts to react, generating heat and carbon dioxide produced by the isocyanate-water reaction.
The carbon dioxide, together with the gases generated by evaporation of any blowing agents, due to the heat generated by the chemical reactions, expands the reactive mixture so as to form the foam; this expansion requires the two containment layers to be adequately contrasted, so as to prevent any deformation thereof, during the foam expansion step.
During the growth and polymerization step, the reactive mixture is contained between the two layers, which are conveyed by means of appropriate movable conveyance and containment systems, such as for example double conveyor belts, with suitable lateral containment systems.
At the exit of the containment and conveyance means, the continuous panel, which by now has polymerized sufficiently, is cut by a cutter into individual panels of the intended length.
In many cases large surfaces need to be covered with the panels and it is therefore necessary to laterally couple the panels together.
For this purpose, the panels usually have appropriately shaped edges so as to allow their lateral mutual joining by means of various interlocking coupling elements and/or overlaps.
Moreover, in some applications it is useful to have panels with integrated lateral engagement systems or inserts which facilitate the assembly and possible disassembly of said panels.
Lateral inserts can be applied easily and rapidly in the case of the production of panels using discontinuous or batch molding methods, in which the inserts are positioned exactly, with the required spacing, inside the mold before the foaming operation.
In the continuous production of panels it is currently very difficult to perform exact automatic insertion of the inserts with a positioning which correctly maintains alignment on the two sides and the required spacing, which may be variable during production, without interrupting the production itself.
The aim of the invention is to solve the above described problem, by providing an apparatus for the continuous production of expanded or foamed plastics panels with inserts on their longitudinal edges which allows the precise positioning of the insert between the layers for containing the panel being manufactured, before foaming the plastic material, so that the plastic material incorporates said inserts and anchors them.
Within this aim, a particular object of the invention is to provide an apparatus which allows to always have a precise reference of the inserts on both sides of the panel, thus contributing to easy positioning.
Another object of the present invention is to provide an apparatus in which it is possible to position the inserts at the intended spacings without thereby having to introduce particular changes to the operating steps.
Another object of the present invention is to provide an apparatus which, thanks to its particular constructive characteristics, is capable of giving the greatest guarantees of reliability and safety in use and is also competitive from a merely economical point of view.
This aim and these and other objects which will become better apparent hereinafter are achieved by an apparatus for the continuous production of expanded plastics panels with inserts on their longitudinal edges, according to the invention, which comprises a head for pouring a reactive mixture between a first and a second containment layers for obtaining a foamed layer, a containment and advancement assembly for said first and second layers being further provided, said assembly being constituted by a lower slat conveyor and by an upper slat conveyor, said lower slat conveyor having lateral containment blocks at the ends of its slats, characterized in that it comprises, on at least some of said blocks, means for engaging the inserts to be incorporated in said foamed layer and means for picking and placing said inserts on said engagement means.